dorsal/arxiv
View SchemaDefinition and measurement of the local density of electromagnetic states close to an interface
| Authors | K. Joulain, R. Carminati, J. -P Mulet, J. -J. Greffet |
|---|---|
| Categories | |
| ArXiv ID | physics/0307018 |
| URL | https://arxiv.org/abs/physics/0307018 |
| DOI | 10.1103/PhysRevB.68.245405 |
Abstract
We propose in this article an unambiguous definition of the local density of electromagnetic states (LDOS) in a vacuum near an interface in an equilibrium situation at temperature $T$. We show that the LDOS depends only on the electric field Green function of the system but does not reduce in general to the trace of its imaginary part as often used in the literature. We illustrate this result by a study of the LDOS variations with the distance to an interface and point out deviations from the standard definition. We show nevertheless that this definition remains correct at frequencies close to the material resonances such as surface polaritons. We also study the feasability of detecting such a LDOS with apetureless SNOM techniques. We first show that a thermal near-field emission spectrum above a sample should be detectable and that this measurement could give access to the electromagnetic LDOS. It is further shown that the apertureless SNOM is the optical analog of the scanning tunneling microscope which is known to detect the electronic LDOS. We also discuss some recent SNOM experiments aimed at detecting the electromagnetic LDOS.
{
"annotation_id": "d1a735fa-5f0c-4828-86e3-afa480211e56",
"date_created": "2026-03-02T18:00:46.090000Z",
"date_modified": "2026-03-02T18:00:46.090000Z",
"file_hash": "745a96f33e76440c14400790927a062ebe649d931ff7dfa3577ba5f771192177",
"private": false,
"record": {
"abstract": "We propose in this article an unambiguous definition of the local density of\nelectromagnetic states (LDOS) in a vacuum near an interface in an equilibrium\nsituation at temperature $T$. We show that the LDOS depends only on the\nelectric field Green function of the system but does not reduce in general to\nthe trace of its imaginary part as often used in the literature. We illustrate\nthis result by a study of the LDOS variations with the distance to an interface\nand point out deviations from the standard definition. We show nevertheless\nthat this definition remains correct at frequencies close to the material\nresonances such as surface polaritons. We also study the feasability of\ndetecting such a LDOS with apetureless SNOM techniques. We first show that a\nthermal near-field emission spectrum above a sample should be detectable and\nthat this measurement could give access to the electromagnetic LDOS. It is\nfurther shown that the apertureless SNOM is the optical analog of the scanning\ntunneling microscope which is known to detect the electronic LDOS. We also\ndiscuss some recent SNOM experiments aimed at detecting the electromagnetic\nLDOS.",
"arxiv_id": "physics/0307018",
"authors": [
"K. Joulain",
"R. Carminati",
"J. -P Mulet",
"J. -J. Greffet"
],
"categories": [
"physics.optics"
],
"doi": "10.1103/PhysRevB.68.245405",
"title": "Definition and measurement of the local density of electromagnetic states close to an interface",
"url": "https://arxiv.org/abs/physics/0307018"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "afce7a01-ffd7-4db0-b311-fe6a25a0db18",
"id": "arXiv Dataset IDs",
"type": "Model",
"variant": "snapshot-2026-03-01",
"version": "0.1.0"
},
"user_id": 1000002
}